An Austrian who stays a step ahead of the U.S. is accused of being part of a global maze of illicit suppliers who are finding gaps in the sanctions campaign.

WASHINGTON — Austrian-born Daniel Frosch was only 23 when U.S. officials first realized that he had become a small but important cog in Iran's illicit weapons programs.

In October 2005, Austrian authorities intercepted a parcel containing graphite cylinders, which can be used in ballistic missiles, addressed to Iran from Frosch's tiny export company in Graz. In late 2006, they tried to arrest him for allegedly attempting to sell valves and other components with military applications to Iranian state-owned companies.

By then Frosch had moved to the United Arab Emirates, which has no extradition treaty with Austria and loose export control rules. Today, U.S. officials say, his Ajman-based International General Resourcing FZE sells banned electronics and other material to Tehran as part of a global maze of illicit suppliers, fly-by-night companies, crooked shipping agents and other corrupt officials in Iran's sanctions-busting schemes.

Underscoring Frosch's significance, the Obama administration slapped sanctions on the businessman three months ago, adding him to dozens of individuals and hundreds of companies on a blacklist for allegedly helping Iran obtain nuclear or ballistic missile technology in violation of United Nations Security Council resolutions.

U.S. officials say the list sends a clear warning to Iran's suppliers that the net is closing. But Frosch's ability to continue selling sensitive equipment and evade prosecution also is a cautionary tale about gaps in the U.S.-led sanctions campaign, which has sent Iran's economy into a tailspin but has yet to persuade its leaders to curb their nuclear program.

"His activities are emblematic of a type of actor that we are especially interested in trying to act against — people who are assisting the government of Iran's efforts to acquire" illegal weapons technology, said a U.S. Treasury official who, like others interviewed for this article, declined to be named because of the case's sensitivity. "Catching these kinds of facilitators is especially rewarding for us."

Capturing Frosch, however, is proving more difficult than identifying him.

His case file was opened in October 2005, when his name came across the desk of U.S. weapons experts in Vienna, home to the International Atomic Energy Agency, the United Nations' nuclear watchdog. It's not clear how he first linked up to Iran, or whether he was operating as a front for others.

Over the next two years, U.S. diplomats and investigators discussed Frosch in nearly 20 meetings with officials in Vienna and Abu Dhabi, United Arab Emirates, according to secret State Department cables published by WikiLeaks.

Frosch "fits the profile of somebody who the Iranians look to work with on proliferation exports," Helmut Krehlik, then a senior official in the Austrian Economics Ministry, told American officials in a January 2006 meeting in Vienna, according to one cable.

"He is young, financially motivated and runs a small company" more willing to assume the risks of illicit dealings with Iran than a larger company, Krehlik said.

Obama administration officials view economic sanctions as a key to forcing Iran to the negotiating table to discuss its disputed nuclear program with the U.S. and five other major powers. Diplomats said over the weekend that Iran was prepared to resume talks, last held in Moscow in June, after the United States' Nov. 6 election.

Austria has long been a small but important trading partner for Iran. Its status as a neutral nation made Vienna a crossroads for espionage during the Cold War, and an occasional source of concern for U.S. officials ever since.

"An enduring theme in our bilateral relations was the nature of problematic contacts between Austrian companies or citizens and what we were then calling 'states of concern,'" said an American official familiar with U.S.-Austrian relations.

Frosch, the official recalled, was "probably among the more notable and enduring" of these cases.

Born in Feldbach, near Austria's border with Hungary, Frosch was barely out of his teens when he started Daniel Frosch Exports, an industrial spare parts company staffed by his father and one other employee. As early as 2003, Krehlik told U.S. officials, Frosch began shipping products with possible military applications to Iran without proper licenses.

Some of the supplies — including the cylinders seized at the Graz airport in 2005 — had been manufactured in the United States, Krehlik said. U.S. customs officials opened a criminal investigation, but no charges were filed, officials said.

When Austrian authorities first confronted Frosch about his shipment of graphite cylinders, he denied wrongdoing and said the parts he sold were for civilian use. He told them his business was struggling and he planned to relocate to Dubai, United Arab Emirates.